Here’s how the hardware part of the hack goes. He removes the speaker from the headset and solders the base of a transistor in-line with a resistor to the red wire. The emitter connects to the grounded frame of the USB charging cable which is plugged into an outlet next to your garage door opener. The collector of the transistor is then connected to the garage door opener, along with a common ground connection, allowing audio from the headset to trigger the transistor to open the door.

The systems is secure based on Bluetooth pairing, which was done with his phone before starting the hardware hack.

You can spoof BT MAC addresses, and since those headsets (including this one) always only have 0000 as code that would be all that is needed to hack this system.
I have different views on what I call secure.

Reliability and the fact that it can go invisible and needs a physical key to be pressed to be paired and it has voice-feedback messages, which he uses to activate.
Plus it’s the one he knows and tested.

But yeah you might find a reasonable cheap one that has the same features.

What scenario are you imagining where this hack would be the difference between getting burgled and not getting burgled? Are there burglars in your area roaming around with RF sensing equipment on the off chance someone has a Bluetooth activated door?

In any case, the problem is that worrying about that stuff is a misallocation of resources. If gaining access to the garage gains you access to the entire house, or grants you access to anything more valuable than a snow shovel and a lawn mower you have much, much bigger problems to deal with before you worry about your choice of wireless door remote protocol.

But if someone can seemingly legitimately get into your garage they can easily close the door and then break down the access door with any tool they like, nobody will be surprised by noise form a garage after all.
As for who would know, how about the guy who sold the kit and his computer, which can be hacked too.

Although admittedly the chances are slim someone finds out they are still existing in a real way. And I can tell you from more than one incident that the damn thieves are always looking for opportunity, and there are more of them than you might think and they are quite brazen.

Just remembered my BT Headset beeps when the battery is low or isn’t paired with a device. Remember to check that before you buy for this project or you’ll be wondering why your garage door is opening and closing until you drive up and connect.

This is why he used a specific model, plus it’s connected to the power supply always so the battery never gets low, and if the power fails in the area the opener won’t have power to operate the door.
It’s still a good reminder though for people trying this on low-cost alternative models.